1 /*
2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "asm/macroAssembler.hpp"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "code/vtableStubs.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "os_share_linux.hpp"
37 #include "prims/jniFastGetField.hpp"
38 #include "prims/jvm.h"
39 #include "prims/jvm_misc.hpp"
40 #include "runtime/arguments.hpp"
41 #include "runtime/extendedPC.hpp"
42 #include "runtime/frame.inline.hpp"
43 #include "runtime/interfaceSupport.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/javaCalls.hpp"
46 #include "runtime/mutexLocker.hpp"
47 #include "runtime/osThread.hpp"
48 #include "runtime/sharedRuntime.hpp"
49 #include "runtime/stubRoutines.hpp"
50 #include "runtime/thread.inline.hpp"
51 #include "runtime/timer.hpp"
52 #include "services/memTracker.hpp"
53 #include "utilities/events.hpp"
54 #include "utilities/vmError.hpp"
55
56 // put OS-includes here
57 # include <sys/types.h>
58 # include <sys/mman.h>
59 # include <pthread.h>
60 # include <signal.h>
61 # include <errno.h>
62 # include <dlfcn.h>
63 # include <stdlib.h>
64 # include <stdio.h>
65 # include <unistd.h>
66 # include <sys/resource.h>
67 # include <pthread.h>
68 # include <sys/stat.h>
69 # include <sys/time.h>
70 # include <sys/utsname.h>
71 # include <sys/socket.h>
72 # include <sys/wait.h>
73 # include <pwd.h>
74 # include <poll.h>
75 # include <ucontext.h>
76 # include <fpu_control.h>
77
78 #ifdef AMD64
79 #define REG_SP REG_RSP
80 #define REG_PC REG_RIP
81 #define REG_FP REG_RBP
82 #define SPELL_REG_SP "rsp"
83 #define SPELL_REG_FP "rbp"
84 #else
85 #define REG_SP REG_UESP
86 #define REG_PC REG_EIP
87 #define REG_FP REG_EBP
88 #define SPELL_REG_SP "esp"
89 #define SPELL_REG_FP "ebp"
90 #endif // AMD64
91
92 address os::current_stack_pointer() {
93 #ifdef SPARC_WORKS
94 register void *esp;
95 __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));
96 return (address) ((char*)esp + sizeof(long)*2);
97 #elif defined(__clang__)
98 intptr_t* esp;
99 __asm__ __volatile__ ("mov %%"SPELL_REG_SP", %0":"=r"(esp):);
100 return (address) esp;
101 #else
102 register void *esp __asm__ (SPELL_REG_SP);
103 return (address) esp;
104 #endif
105 }
106
107 char* os::non_memory_address_word() {
108 // Must never look like an address returned by reserve_memory,
109 // even in its subfields (as defined by the CPU immediate fields,
110 // if the CPU splits constants across multiple instructions).
111
112 return (char*) -1;
113 }
114
115 void os::initialize_thread(Thread* thr) {
116 // Nothing to do.
117 }
118
119 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
120 return (address)uc->uc_mcontext.gregs[REG_PC];
121 }
122
123 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
124 uc->uc_mcontext.gregs[REG_PC] = (intptr_t)pc;
125 }
126
127 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
128 return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
129 }
130
131 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
132 return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
133 }
134
135 // For Forte Analyzer AsyncGetCallTrace profiling support - thread
136 // is currently interrupted by SIGPROF.
137 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal
138 // frames. Currently we don't do that on Linux, so it's the same as
139 // os::fetch_frame_from_context().
140 // This method is also used for stack overflow signal handling.
141 ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
142 const ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {
143
144 assert(thread != NULL, "just checking");
145 assert(ret_sp != NULL, "just checking");
146 assert(ret_fp != NULL, "just checking");
147
148 return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
149 }
150
151 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
152 intptr_t** ret_sp, intptr_t** ret_fp) {
153
154 ExtendedPC epc;
155 const ucontext_t* uc = (const ucontext_t*)ucVoid;
156
157 if (uc != NULL) {
158 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
159 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
160 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
161 } else {
162 // construct empty ExtendedPC for return value checking
163 epc = ExtendedPC(NULL);
164 if (ret_sp) *ret_sp = (intptr_t *)NULL;
165 if (ret_fp) *ret_fp = (intptr_t *)NULL;
166 }
167
168 return epc;
169 }
170
171 frame os::fetch_frame_from_context(const void* ucVoid) {
172 intptr_t* sp;
173 intptr_t* fp;
174 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
175 return frame(sp, fp, epc.pc());
176 }
177
178 frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
179 intptr_t* sp;
180 intptr_t* fp;
181 ExtendedPC epc = os::Linux::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, &fp);
182 return frame(sp, fp, epc.pc());
183 }
184
185 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
186 address pc = (address) os::Linux::ucontext_get_pc(uc);
187 if (Interpreter::contains(pc)) {
188 // interpreter performs stack banging after the fixed frame header has
189 // been generated while the compilers perform it before. To maintain
190 // semantic consistency between interpreted and compiled frames, the
191 // method returns the Java sender of the current frame.
192 *fr = os::fetch_frame_from_ucontext(thread, uc);
193 if (!fr->is_first_java_frame()) {
194 assert(fr->safe_for_sender(thread), "Safety check");
195 *fr = fr->java_sender();
196 }
197 } else {
198 // more complex code with compiled code
199 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
200 CodeBlob* cb = CodeCache::find_blob(pc);
201 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
202 // Not sure where the pc points to, fallback to default
203 // stack overflow handling
204 return false;
205 } else {
206 // in compiled code, the stack banging is performed just after the return pc
207 // has been pushed on the stack
208 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
209 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
210 *fr = frame(sp + 1, fp, (address)*sp);
211 if (!fr->is_java_frame()) {
212 assert(fr->safe_for_sender(thread), "Safety check");
213 assert(!fr->is_first_frame(), "Safety check");
214 *fr = fr->java_sender();
215 }
216 }
217 }
218 assert(fr->is_java_frame(), "Safety check");
219 return true;
220 }
221
222 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get
223 // turned off by -fomit-frame-pointer,
224 frame os::get_sender_for_C_frame(frame* fr) {
225 return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
226 }
227
228 intptr_t* _get_previous_fp() {
229 #ifdef SPARC_WORKS
230 register intptr_t **ebp;
231 __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
232 #elif defined(__clang__)
233 intptr_t **ebp;
234 __asm__ __volatile__ ("mov %%"SPELL_REG_FP", %0":"=r"(ebp):);
235 #else
236 register intptr_t **ebp __asm__ (SPELL_REG_FP);
237 #endif
238 // ebp is for this frame (_get_previous_fp). We want the ebp for the
239 // caller of os::current_frame*(), so go up two frames. However, for
240 // optimized builds, _get_previous_fp() will be inlined, so only go
241 // up 1 frame in that case.
242 #ifdef _NMT_NOINLINE_
243 return **(intptr_t***)ebp;
244 #else
245 return *ebp;
246 #endif
247 }
248
249
250 frame os::current_frame() {
251 intptr_t* fp = _get_previous_fp();
252 frame myframe((intptr_t*)os::current_stack_pointer(),
253 (intptr_t*)fp,
254 CAST_FROM_FN_PTR(address, os::current_frame));
255 if (os::is_first_C_frame(&myframe)) {
256 // stack is not walkable
257 return frame();
258 } else {
259 return os::get_sender_for_C_frame(&myframe);
260 }
261 }
262
263 // Utility functions
264
265 // From IA32 System Programming Guide
266 enum {
267 trap_page_fault = 0xE
268 };
269
270 extern "C" JNIEXPORT int
271 JVM_handle_linux_signal(int sig,
272 siginfo_t* info,
273 void* ucVoid,
274 int abort_if_unrecognized) {
275 ucontext_t* uc = (ucontext_t*) ucVoid;
276
277 Thread* t = Thread::current_or_null_safe();
278
279 // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
280 // (no destructors can be run)
281 os::WatcherThreadCrashProtection::check_crash_protection(sig, t);
282
283 SignalHandlerMark shm(t);
284
285 // Note: it's not uncommon that JNI code uses signal/sigset to install
286 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
287 // or have a SIGILL handler when detecting CPU type). When that happens,
288 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
289 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
290 // that do not require siginfo/ucontext first.
291
292 if (sig == SIGPIPE || sig == SIGXFSZ) {
293 // allow chained handler to go first
294 if (os::Linux::chained_handler(sig, info, ucVoid)) {
295 return true;
296 } else {
297 // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
298 return true;
299 }
300 }
301
302 JavaThread* thread = NULL;
303 VMThread* vmthread = NULL;
304 if (os::Linux::signal_handlers_are_installed) {
305 if (t != NULL ){
306 if(t->is_Java_thread()) {
307 thread = (JavaThread*)t;
308 }
309 else if(t->is_VM_thread()){
310 vmthread = (VMThread *)t;
311 }
312 }
313 }
314 /*
315 NOTE: does not seem to work on linux.
316 if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {
317 // can't decode this kind of signal
318 info = NULL;
319 } else {
320 assert(sig == info->si_signo, "bad siginfo");
321 }
322 */
323 // decide if this trap can be handled by a stub
324 address stub = NULL;
325
326 address pc = NULL;
327
328 //%note os_trap_1
329 if (info != NULL && uc != NULL && thread != NULL) {
330 pc = (address) os::Linux::ucontext_get_pc(uc);
331
332 if (StubRoutines::is_safefetch_fault(pc)) {
333 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
334 return 1;
335 }
336
337 #ifndef AMD64
338 // Halt if SI_KERNEL before more crashes get misdiagnosed as Java bugs
339 // This can happen in any running code (currently more frequently in
340 // interpreter code but has been seen in compiled code)
341 if (sig == SIGSEGV && info->si_addr == 0 && info->si_code == SI_KERNEL) {
342 fatal("An irrecoverable SI_KERNEL SIGSEGV has occurred due "
343 "to unstable signal handling in this distribution.");
344 }
345 #endif // AMD64
346
347 // Handle ALL stack overflow variations here
348 if (sig == SIGSEGV) {
349 address addr = (address) info->si_addr;
350
351 // check if fault address is within thread stack
352 if (thread->on_local_stack(addr)) {
353 // stack overflow
354 if (thread->in_stack_yellow_reserved_zone(addr)) {
355 if (thread->thread_state() == _thread_in_Java) {
356 if (thread->in_stack_reserved_zone(addr)) {
357 frame fr;
358 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
359 assert(fr.is_java_frame(), "Must be a Java frame");
360 frame activation =
361 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
362 if (activation.sp() != NULL) {
363 thread->disable_stack_reserved_zone();
364 if (activation.is_interpreted_frame()) {
365 thread->set_reserved_stack_activation((address)(
366 activation.fp() + frame::interpreter_frame_initial_sp_offset));
367 } else {
368 thread->set_reserved_stack_activation((address)activation.unextended_sp());
369 }
370 return 1;
371 }
372 }
373 }
374 // Throw a stack overflow exception. Guard pages will be reenabled
375 // while unwinding the stack.
376 thread->disable_stack_yellow_reserved_zone();
377 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
378 } else {
379 // Thread was in the vm or native code. Return and try to finish.
380 thread->disable_stack_yellow_reserved_zone();
381 return 1;
382 }
383 } else if (thread->in_stack_red_zone(addr)) {
384 // Fatal red zone violation. Disable the guard pages and fall through
385 // to handle_unexpected_exception way down below.
386 thread->disable_stack_red_zone();
387 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
388
389 // This is a likely cause, but hard to verify. Let's just print
390 // it as a hint.
391 tty->print_raw_cr("Please check if any of your loaded .so files has "
392 "enabled executable stack (see man page execstack(8))");
393 } else {
394 // Accessing stack address below sp may cause SEGV if current
395 // thread has MAP_GROWSDOWN stack. This should only happen when
396 // current thread was created by user code with MAP_GROWSDOWN flag
397 // and then attached to VM. See notes in os_linux.cpp.
398 if (thread->osthread()->expanding_stack() == 0) {
399 thread->osthread()->set_expanding_stack();
400 if (os::Linux::manually_expand_stack(thread, addr)) {
401 thread->osthread()->clear_expanding_stack();
402 return 1;
403 }
404 thread->osthread()->clear_expanding_stack();
405 } else {
406 fatal("recursive segv. expanding stack.");
407 }
408 }
409 }
410 }
411
412 if ((sig == SIGSEGV) && VM_Version::is_cpuinfo_segv_addr(pc)) {
413 // Verify that OS save/restore AVX registers.
414 stub = VM_Version::cpuinfo_cont_addr();
415 }
416
417 if (thread->thread_state() == _thread_in_Java) {
418 // Java thread running in Java code => find exception handler if any
419 // a fault inside compiled code, the interpreter, or a stub
420
421 if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
422 stub = SharedRuntime::get_poll_stub(pc);
423 } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {
424 // BugId 4454115: A read from a MappedByteBuffer can fault
425 // here if the underlying file has been truncated.
426 // Do not crash the VM in such a case.
427 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
428 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
429 if (nm != NULL && nm->has_unsafe_access()) {
430 address next_pc = Assembler::locate_next_instruction(pc);
431 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
432 }
433 }
434 else
435
436 #ifdef AMD64
437 if (sig == SIGFPE &&
438 (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {
439 stub =
440 SharedRuntime::
441 continuation_for_implicit_exception(thread,
442 pc,
443 SharedRuntime::
444 IMPLICIT_DIVIDE_BY_ZERO);
445 #else
446 if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {
447 // HACK: si_code does not work on linux 2.2.12-20!!!
448 int op = pc[0];
449 if (op == 0xDB) {
450 // FIST
451 // TODO: The encoding of D2I in i486.ad can cause an exception
452 // prior to the fist instruction if there was an invalid operation
453 // pending. We want to dismiss that exception. From the win_32
454 // side it also seems that if it really was the fist causing
455 // the exception that we do the d2i by hand with different
456 // rounding. Seems kind of weird.
457 // NOTE: that we take the exception at the NEXT floating point instruction.
458 assert(pc[0] == 0xDB, "not a FIST opcode");
459 assert(pc[1] == 0x14, "not a FIST opcode");
460 assert(pc[2] == 0x24, "not a FIST opcode");
461 return true;
462 } else if (op == 0xF7) {
463 // IDIV
464 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
465 } else {
466 // TODO: handle more cases if we are using other x86 instructions
467 // that can generate SIGFPE signal on linux.
468 tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);
469 fatal("please update this code.");
470 }
471 #endif // AMD64
472 } else if (sig == SIGSEGV &&
473 !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {
474 // Determination of interpreter/vtable stub/compiled code null exception
475 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
476 }
477 } else if (thread->thread_state() == _thread_in_vm &&
478 sig == SIGBUS && /* info->si_code == BUS_OBJERR && */
479 thread->doing_unsafe_access()) {
480 address next_pc = Assembler::locate_next_instruction(pc);
481 stub = SharedRuntime::handle_unsafe_access(thread, next_pc);
482 }
483
484 // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
485 // and the heap gets shrunk before the field access.
486 if ((sig == SIGSEGV) || (sig == SIGBUS)) {
487 address addr = JNI_FastGetField::find_slowcase_pc(pc);
488 if (addr != (address)-1) {
489 stub = addr;
490 }
491 }
492
493 // Check to see if we caught the safepoint code in the
494 // process of write protecting the memory serialization page.
495 // It write enables the page immediately after protecting it
496 // so we can just return to retry the write.
497 if ((sig == SIGSEGV) &&
498 os::is_memory_serialize_page(thread, (address) info->si_addr)) {
499 // Block current thread until the memory serialize page permission restored.
500 os::block_on_serialize_page_trap();
501 return true;
502 }
503 }
504
505 #ifndef AMD64
506 // Execution protection violation
507 //
508 // This should be kept as the last step in the triage. We don't
509 // have a dedicated trap number for a no-execute fault, so be
510 // conservative and allow other handlers the first shot.
511 //
512 // Note: We don't test that info->si_code == SEGV_ACCERR here.
513 // this si_code is so generic that it is almost meaningless; and
514 // the si_code for this condition may change in the future.
515 // Furthermore, a false-positive should be harmless.
516 if (UnguardOnExecutionViolation > 0 &&
517 (sig == SIGSEGV || sig == SIGBUS) &&
518 uc->uc_mcontext.gregs[REG_TRAPNO] == trap_page_fault) {
519 int page_size = os::vm_page_size();
520 address addr = (address) info->si_addr;
521 address pc = os::Linux::ucontext_get_pc(uc);
522 // Make sure the pc and the faulting address are sane.
523 //
524 // If an instruction spans a page boundary, and the page containing
525 // the beginning of the instruction is executable but the following
526 // page is not, the pc and the faulting address might be slightly
527 // different - we still want to unguard the 2nd page in this case.
528 //
529 // 15 bytes seems to be a (very) safe value for max instruction size.
530 bool pc_is_near_addr =
531 (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);
532 bool instr_spans_page_boundary =
533 (align_size_down((intptr_t) pc ^ (intptr_t) addr,
534 (intptr_t) page_size) > 0);
535
536 if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {
537 static volatile address last_addr =
538 (address) os::non_memory_address_word();
539
540 // In conservative mode, don't unguard unless the address is in the VM
541 if (addr != last_addr &&
542 (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {
543
544 // Set memory to RWX and retry
545 address page_start =
546 (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
547 bool res = os::protect_memory((char*) page_start, page_size,
548 os::MEM_PROT_RWX);
549
550 log_debug(os)("Execution protection violation "
551 "at " INTPTR_FORMAT
552 ", unguarding " INTPTR_FORMAT ": %s, errno=%d", p2i(addr),
553 p2i(page_start), (res ? "success" : "failed"), errno);
554 stub = pc;
555
556 // Set last_addr so if we fault again at the same address, we don't end
557 // up in an endless loop.
558 //
559 // There are two potential complications here. Two threads trapping at
560 // the same address at the same time could cause one of the threads to
561 // think it already unguarded, and abort the VM. Likely very rare.
562 //
563 // The other race involves two threads alternately trapping at
564 // different addresses and failing to unguard the page, resulting in
565 // an endless loop. This condition is probably even more unlikely than
566 // the first.
567 //
568 // Although both cases could be avoided by using locks or thread local
569 // last_addr, these solutions are unnecessary complication: this
570 // handler is a best-effort safety net, not a complete solution. It is
571 // disabled by default and should only be used as a workaround in case
572 // we missed any no-execute-unsafe VM code.
573
574 last_addr = addr;
575 }
576 }
577 }
578 #endif // !AMD64
579
580 if (stub != NULL) {
581 // save all thread context in case we need to restore it
582 if (thread != NULL) thread->set_saved_exception_pc(pc);
583
584 os::Linux::ucontext_set_pc(uc, stub);
585 return true;
586 }
587
588 // signal-chaining
589 if (os::Linux::chained_handler(sig, info, ucVoid)) {
590 return true;
591 }
592
593 if (!abort_if_unrecognized) {
594 // caller wants another chance, so give it to him
595 return false;
596 }
597
598 if (pc == NULL && uc != NULL) {
599 pc = os::Linux::ucontext_get_pc(uc);
600 }
601
602 // unmask current signal
603 sigset_t newset;
604 sigemptyset(&newset);
605 sigaddset(&newset, sig);
606 sigprocmask(SIG_UNBLOCK, &newset, NULL);
607
608 VMError::report_and_die(t, sig, pc, info, ucVoid);
609
610 ShouldNotReachHere();
611 return true; // Mute compiler
612 }
613
614 void os::Linux::init_thread_fpu_state(void) {
615 #ifndef AMD64
616 // set fpu to 53 bit precision
617 set_fpu_control_word(0x27f);
618 #endif // !AMD64
619 }
620
621 int os::Linux::get_fpu_control_word(void) {
622 #ifdef AMD64
623 return 0;
624 #else
625 int fpu_control;
626 _FPU_GETCW(fpu_control);
627 return fpu_control & 0xffff;
628 #endif // AMD64
629 }
630
631 void os::Linux::set_fpu_control_word(int fpu_control) {
632 #ifndef AMD64
633 _FPU_SETCW(fpu_control);
634 #endif // !AMD64
635 }
636
637 // Check that the linux kernel version is 2.4 or higher since earlier
638 // versions do not support SSE without patches.
639 bool os::supports_sse() {
640 #ifdef AMD64
641 return true;
642 #else
643 struct utsname uts;
644 if( uname(&uts) != 0 ) return false; // uname fails?
645 char *minor_string;
646 int major = strtol(uts.release,&minor_string,10);
647 int minor = strtol(minor_string+1,NULL,10);
648 bool result = (major > 2 || (major==2 && minor >= 4));
649 log_info(os)("OS version is %d.%d, which %s support SSE/SSE2",
650 major,minor, result ? "DOES" : "does NOT");
651 return result;
652 #endif // AMD64
653 }
654
655 bool os::is_allocatable(size_t bytes) {
656 #ifdef AMD64
657 // unused on amd64?
658 return true;
659 #else
660
661 if (bytes < 2 * G) {
662 return true;
663 }
664
665 char* addr = reserve_memory(bytes, NULL);
666
667 if (addr != NULL) {
668 release_memory(addr, bytes);
669 }
670
671 return addr != NULL;
672 #endif // AMD64
673 }
674
675 ////////////////////////////////////////////////////////////////////////////////
676 // thread stack
677
678 #ifdef AMD64
679 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
680 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
681 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
682 #else
683 size_t os::Posix::_compiler_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
684 size_t os::Posix::_java_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
685 size_t os::Posix::_vm_internal_thread_min_stack_allowed = (48 DEBUG_ONLY(+ 4)) * K;
686 #endif // AMD64
687
688 // return default stack size for thr_type
689 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
690 // default stack size (compiler thread needs larger stack)
691 #ifdef AMD64
692 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
693 #else
694 size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);
695 #endif // AMD64
696 return s;
697 }
698
699 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
700 // Creating guard page is very expensive. Java thread has HotSpot
701 // guard page, only enable glibc guard page for non-Java threads.
702 return (thr_type == java_thread ? 0 : page_size());
703 }
704
705 // Java thread:
706 //
707 // Low memory addresses
708 // +------------------------+
709 // | |\ JavaThread created by VM does not have glibc
710 // | glibc guard page | - guard, attached Java thread usually has
711 // | |/ 1 page glibc guard.
712 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
713 // | |\
714 // | HotSpot Guard Pages | - red and yellow pages
715 // | |/
716 // +------------------------+ JavaThread::stack_yellow_zone_base()
717 // | |\
718 // | Normal Stack | -
719 // | |/
720 // P2 +------------------------+ Thread::stack_base()
721 //
722 // Non-Java thread:
723 //
724 // Low memory addresses
725 // +------------------------+
726 // | |\
727 // | glibc guard page | - usually 1 page
728 // | |/
729 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
730 // | |\
731 // | Normal Stack | -
732 // | |/
733 // P2 +------------------------+ Thread::stack_base()
734 //
735 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
736 // pthread_attr_getstack()
737
738 static void current_stack_region(address * bottom, size_t * size) {
739 if (os::Linux::is_initial_thread()) {
740 // initial thread needs special handling because pthread_getattr_np()
741 // may return bogus value.
742 *bottom = os::Linux::initial_thread_stack_bottom();
743 *size = os::Linux::initial_thread_stack_size();
744 } else {
745 pthread_attr_t attr;
746
747 int rslt = pthread_getattr_np(pthread_self(), &attr);
748
749 // JVM needs to know exact stack location, abort if it fails
750 if (rslt != 0) {
751 if (rslt == ENOMEM) {
752 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
753 } else {
754 fatal("pthread_getattr_np failed with errno = %d", rslt);
755 }
756 }
757
758 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
759 fatal("Can not locate current stack attributes!");
760 }
761
762 pthread_attr_destroy(&attr);
763
764 }
765 assert(os::current_stack_pointer() >= *bottom &&
766 os::current_stack_pointer() < *bottom + *size, "just checking");
767 }
768
769 address os::current_stack_base() {
770 address bottom;
771 size_t size;
772 current_stack_region(&bottom, &size);
773 return (bottom + size);
774 }
775
776 size_t os::current_stack_size() {
777 // stack size includes normal stack and HotSpot guard pages
778 address bottom;
779 size_t size;
780 current_stack_region(&bottom, &size);
781 return size;
782 }
783
784 /////////////////////////////////////////////////////////////////////////////
785 // helper functions for fatal error handler
786
787 void os::print_context(outputStream *st, const void *context) {
788 if (context == NULL) return;
789
790 const ucontext_t *uc = (const ucontext_t*)context;
791 st->print_cr("Registers:");
792 #ifdef AMD64
793 st->print( "RAX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RAX]);
794 st->print(", RBX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBX]);
795 st->print(", RCX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RCX]);
796 st->print(", RDX=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDX]);
797 st->cr();
798 st->print( "RSP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSP]);
799 st->print(", RBP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RBP]);
800 st->print(", RSI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RSI]);
801 st->print(", RDI=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RDI]);
802 st->cr();
803 st->print( "R8 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R8]);
804 st->print(", R9 =" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R9]);
805 st->print(", R10=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R10]);
806 st->print(", R11=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R11]);
807 st->cr();
808 st->print( "R12=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R12]);
809 st->print(", R13=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R13]);
810 st->print(", R14=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R14]);
811 st->print(", R15=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_R15]);
812 st->cr();
813 st->print( "RIP=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_RIP]);
814 st->print(", EFLAGS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_EFL]);
815 st->print(", CSGSFS=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_CSGSFS]);
816 st->print(", ERR=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_ERR]);
817 st->cr();
818 st->print(" TRAPNO=" INTPTR_FORMAT, (intptr_t)uc->uc_mcontext.gregs[REG_TRAPNO]);
819 #else
820 st->print( "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EAX]);
821 st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBX]);
822 st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ECX]);
823 st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDX]);
824 st->cr();
825 st->print( "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_UESP]);
826 st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EBP]);
827 st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_ESI]);
828 st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EDI]);
829 st->cr();
830 st->print( "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EIP]);
831 st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_EFL]);
832 st->print(", CR2=" PTR64_FORMAT, (uint64_t)uc->uc_mcontext.cr2);
833 #endif // AMD64
834 st->cr();
835 st->cr();
836
837 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
838 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
839 print_hex_dump(st, (address)sp, (address)(sp + 8), sizeof(intptr_t));
840 st->cr();
841
842 // Note: it may be unsafe to inspect memory near pc. For example, pc may
843 // point to garbage if entry point in an nmethod is corrupted. Leave
844 // this at the end, and hope for the best.
845 address pc = os::Linux::ucontext_get_pc(uc);
846 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
847 print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
848 }
849
850 void os::print_register_info(outputStream *st, const void *context) {
851 if (context == NULL) return;
852
853 const ucontext_t *uc = (const ucontext_t*)context;
854
855 st->print_cr("Register to memory mapping:");
856 st->cr();
857
858 // this is horrendously verbose but the layout of the registers in the
859 // context does not match how we defined our abstract Register set, so
860 // we can't just iterate through the gregs area
861
862 // this is only for the "general purpose" registers
863
864 #ifdef AMD64
865 st->print("RAX="); print_location(st, uc->uc_mcontext.gregs[REG_RAX]);
866 st->print("RBX="); print_location(st, uc->uc_mcontext.gregs[REG_RBX]);
867 st->print("RCX="); print_location(st, uc->uc_mcontext.gregs[REG_RCX]);
868 st->print("RDX="); print_location(st, uc->uc_mcontext.gregs[REG_RDX]);
869 st->print("RSP="); print_location(st, uc->uc_mcontext.gregs[REG_RSP]);
870 st->print("RBP="); print_location(st, uc->uc_mcontext.gregs[REG_RBP]);
871 st->print("RSI="); print_location(st, uc->uc_mcontext.gregs[REG_RSI]);
872 st->print("RDI="); print_location(st, uc->uc_mcontext.gregs[REG_RDI]);
873 st->print("R8 ="); print_location(st, uc->uc_mcontext.gregs[REG_R8]);
874 st->print("R9 ="); print_location(st, uc->uc_mcontext.gregs[REG_R9]);
875 st->print("R10="); print_location(st, uc->uc_mcontext.gregs[REG_R10]);
876 st->print("R11="); print_location(st, uc->uc_mcontext.gregs[REG_R11]);
877 st->print("R12="); print_location(st, uc->uc_mcontext.gregs[REG_R12]);
878 st->print("R13="); print_location(st, uc->uc_mcontext.gregs[REG_R13]);
879 st->print("R14="); print_location(st, uc->uc_mcontext.gregs[REG_R14]);
880 st->print("R15="); print_location(st, uc->uc_mcontext.gregs[REG_R15]);
881 #else
882 st->print("EAX="); print_location(st, uc->uc_mcontext.gregs[REG_EAX]);
883 st->print("EBX="); print_location(st, uc->uc_mcontext.gregs[REG_EBX]);
884 st->print("ECX="); print_location(st, uc->uc_mcontext.gregs[REG_ECX]);
885 st->print("EDX="); print_location(st, uc->uc_mcontext.gregs[REG_EDX]);
886 st->print("ESP="); print_location(st, uc->uc_mcontext.gregs[REG_ESP]);
887 st->print("EBP="); print_location(st, uc->uc_mcontext.gregs[REG_EBP]);
888 st->print("ESI="); print_location(st, uc->uc_mcontext.gregs[REG_ESI]);
889 st->print("EDI="); print_location(st, uc->uc_mcontext.gregs[REG_EDI]);
890 #endif // AMD64
891
892 st->cr();
893 }
894
895 void os::setup_fpu() {
896 #ifndef AMD64
897 address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
898 __asm__ volatile ( "fldcw (%0)" :
899 : "r" (fpu_cntrl) : "memory");
900 #endif // !AMD64
901 }
902
903 #ifndef PRODUCT
904 void os::verify_stack_alignment() {
905 #ifdef AMD64
906 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
907 #endif
908 }
909 #endif
910
911
912 /*
913 * IA32 only: execute code at a high address in case buggy NX emulation is present. I.e. avoid CS limit
914 * updates (JDK-8023956).
915 */
916 void os::workaround_expand_exec_shield_cs_limit() {
917 #if defined(IA32)
918 size_t page_size = os::vm_page_size();
919 /*
920 * Take the highest VA the OS will give us and exec
921 *
922 * Although using -(pagesz) as mmap hint works on newer kernel as you would
923 * think, older variants affected by this work-around don't (search forward only).
924 *
925 * On the affected distributions, we understand the memory layout to be:
926 *
927 * TASK_LIMIT= 3G, main stack base close to TASK_LIMT.
928 *
929 * A few pages south main stack will do it.
930 *
931 * If we are embedded in an app other than launcher (initial != main stack),
932 * we don't have much control or understanding of the address space, just let it slide.
933 */
934 char* hint = (char*)(Linux::initial_thread_stack_bottom() -
935 (JavaThread::stack_guard_zone_size() + page_size));
936 char* codebuf = os::attempt_reserve_memory_at(page_size, hint);
937 if ((codebuf == NULL) || (!os::commit_memory(codebuf, page_size, true))) {
938 return; // No matter, we tried, best effort.
939 }
940
941 MemTracker::record_virtual_memory_type((address)codebuf, mtInternal);
942
943 log_info(os)("[CS limit NX emulation work-around, exec code at: %p]", codebuf);
944
945 // Some code to exec: the 'ret' instruction
946 codebuf[0] = 0xC3;
947
948 // Call the code in the codebuf
949 __asm__ volatile("call *%0" : : "r"(codebuf));
950
951 // keep the page mapped so CS limit isn't reduced.
952 #endif
953 }
954
955 int os::extra_bang_size_in_bytes() {
956 // JDK-8050147 requires the full cache line bang for x86.
957 return VM_Version::L1_line_size();
958 }